Glucose-6-phosphatase converts glucose-6-phosphate to glucose

Muscle tissue lacks glucose-6-phosphatase enzyme(this enzyme is present in liver) so it cannot convert glucose-6-phosphate to glucose

Glucose-6-phosphate, which is release from muscle glycogen, will goes to liver and converted to glucose.

So muscle tissue cannot directly contribute for blood glucose, it's need help of liver enzyme for coversion from glucose - 6 phosphate to glucose.

Glucose-6-phosphate undergoes glycolysis in muscle tissue to produce ATP for muscle contraction